Moussaoui, now 53, had entered the country on a student visa, took small-plane flight training in Oklahoma, then moved to Minnesota to train on a jumbo jet. His actions raised suspicions with the instructors, and he was arrested in August 2001. “Our theory of the case was that Moussaoui was a backup pilot,” Spencer said, approved by Osama bin Laden personally to travel and train in the United States, and funded with $10,000 from an al-Qaeda operative in Germany.